1) Field of the Invention
The present invention relates to the analysis of chemicals and, in particular, to an apparatus and method for automated chemical analysis of sample fluids, such as samples of a solution for metal processing.
2) Description of Related Art
Chemical analysis is a requirement for a variety of different processes, including the manufacture of chemicals, the chemical treatment of metals, and the like. For example, in a typical aluminum chemical milling process, an aluminum workpiece is selectively exposed to a hot, caustic chemical etchant such as sodium hydroxide. The sodium hydroxide can be provided in an etching solution in a vat in which the aluminum workpiece is immersed. The sodium hydroxide reacts with the aluminum of the workpiece, and material is chemically removed, i.e., etched, from the exposed surfaces of the workpiece. As the etching of multiple workpieces occurs, the content of sodium hydroxide in the etching solution is reduced and the content of aluminum in the solution increases. The decrease in sodium hydroxide and the increase in aluminum decrease the etching effectiveness of the solution, requiring longer periods for etching.
To improve the effectiveness of the process, the etching solution can be replaced, or a regeneration process can be conducted to restore the sodium hydroxide to the solution and remove the aluminum from the solution. Typically, the solution is tested periodically to determine if the solution should be replaced or regenerated. For example, a chemical test can be performed to determine the content of the sodium hydroxide and/or the aluminum in the solution. If regeneration of the solution is to be performed, the information regarding the content of the solution can also be used to determine how the regeneration process should be performed. For example, the volume of sodium hydroxide and other chemicals that are added to the solution during regeneration can be determined according to the content of the solution when regeneration occurs. Testing of the solution is typically performed manually by a technician. The technician must go to the site of the etching process, remove a sample of the solution, and take the sample to a lab for testing. The testing process is labor-intensive and time-consuming. Further, during the delay required for testing, the content of the solution may change, thereby decreasing the accuracy of the results.
Thus, there exists a need for an apparatus and method for automatically chemically analyzing sample fluids. The apparatus and method should not be overly complex and should preferably provide results quickly and accurately. In addition, the apparatus should be capable of analyzing a plurality of solutions, such as the various solutions used in or resulting from an etching process. Further, the apparatus should be capable of storing and/or communicating the results of the analysis, for example, to a remote user.